大全补充22篇第四篇-大全67

gracezz · 发表于 2010-4-21 11:26:03

Passage 67 (4/22)About twice every century, one of the massive stars in our galaxy blows itself apart in a supernova explosion that sends massive quantities of radiation and matter into space and generates shock waves that sweep through the arms (a narrow extension of a larger area, mass, or group)of the galaxy. The shock waves heat the interstellar gas, evaporate small clouds, and compress larger ones to the point at which they collapse under their own gravity to form new stars. The general picture that has been developed for the supernova explosion and its aftermath goes something like this. Throughout its evolution, a star is much like a leaky balloon. It keeps its equilibrium figure through a balance of internal pressure against the tendency to collapse under its own weight. The pressure is generated by nuclear reactions in the core of the star which must continually supply energy to balance the energy that leaks out (leak out: v.泄漏) in the form of radiation. Eventually the nuclear fuel is exhausted, and the pressure drops in the core. With nothing to hold it up, the matter in the center of the star collapses inward, creating higher and higher densities and temperatures, until the nuclei and electrons are fused into a super-dense lump of matter known as a neutron star.
As the overlying layers rain down (rain down: v.大量降下) on the surface of the neutron star, the temperature rises, until with a blinding flash of radiation, the collapse is reversed. A thermonuclear (thermonuclear: adj.高热原子核反应的) shock wave runs through the now expanding stellar envelope, fusing lighter elements into heavier ones and producing a brilliant visual outburst that can be as intense as the light of 10 billion suns. The shell of matter thrown off by the explosion plows through the surrounding gas, producing an expanding bubble of hot gas, with gas temperatures in the millions of degrees. This gas will emit most of its energy at X-ray wavelengths, so it is not surprising that X-ray observatories have provided some of the most useful insights into the nature of the supernova phenomenon. More than twenty supernova remnants have now been detected in X-ray studies.
Recent discoveries of meteorites with anomalous concentrations of certain isotopes indicate that a supernova might have precipitated the birth of our solar system more than four and a half billion years ago. Although the cloud that collapsed to form the Sun and the planets was composed primarily of hydrogen and helium, it also contained carbon, nitrogen, and oxygen, elements essential for life as we know it. Elements heavier than helium are manufactured deep in the interior of stars and would, for the most part (for the most part: adv.在极大程度上), remain there if it were not for the cataclysmic supernova explosions that blow giant stars apart. Additionally, supernovas produce clouds of high-energy particles called cosmic rays (cosmic rays: n. 宇宙线，宇宙射线). These high-energy particles continually bombard the Earth and are responsible for many of the genetic mutations that are the driving force of the evolution of species.

3.According to the passage all of the following are true of supernovas EXCEPT that they
(A) are extremely bright
(B) are an explosion of some sort
(C) emit large quantities of X-rays
(D) result in the destruction of a neutron star（E）

(E) are caused by the collision of large galaxies

8.According to the passage a neutron star is
(A) a gaseous cloud containing heavy elements
(B) an intermediate stage between an ordinary star and a supernova
(C) the residue that is left by a supernova
(D) the core of an ordinary star that houses the thermonuclear reactions（B）

(E) one of billions of meteors that are scattered across the galaxy by a supernova
这两道题的定位在哪里呢？请版主帮忙看一下好吗？十分感谢。

3.According to the passage all of the following are true of supernovas EXCEPT that they
(A) are extremely bright
(B) are an explosion of some sort
(C) emit large quantities of X-rays
(D) result in the destruction of a neutron star（E）

(E) are caused by the collision of large galaxies

8.According to the passage a neutron star is
(A) a gaseous cloud containing heavy elements
(B) an intermediate stage between an ordinary star and a supernova
(C) the residue that is left by a supernova
(D) the core of an ordinary star that houses the thermonuclear reactions（B）

(E) one of billions of meteors that are scattered across the galaxy by a supernova
这两道题的定位在哪里呢？请版主帮忙看一下好吗？十分感谢。

AmyGMAT · 发表于 2010-4-30 00:54:57

About twice everycentury, one of the massive stars in our galaxy blows itself apart ina supernova explosion3B that sends massive quantities of radiation andmatter into space and generates shock waves that sweep through the arms (a narrowextension of a larger area, mass, or group) of the galaxy. Theshock waves heat the interstellar gas, evaporate small clouds, and compresslarger ones to the point at which they collapse under their own gravity to formnew stars. The general picture that has been developed for the supernovaexplosion and its aftermath goes something like this. Throughout its evolution,a star开始只是一个普通的star is much like a leaky balloon. It keeps its equilibrium figurethrough a balance of internal pressure against the tendency to collapse underits own weight. The pressure is generated by nuclear reactions in the core ofthe star which must continually supply energy to balance the energy that leaks out (leak out:v.泄漏) in the form of radiation. Eventually the nuclear fuel is exhausted,and the pressure drops in the core. With nothing to hold it up, the matter in the center of the star collapses inward,creating higher and higher densities and temperatures, until the nuclei andelectrons are fused into a super-dense lump of matter known as a neutron star.经过一系列的过程变成了a neutron star。然后下一段讲到了a neutron star是如何变成supernova的
As the overlyinglayers rain down (rain down: v.大量降下) on the surface of theneutron star, the temperature rises, until with a blinding flash ofradiation, the collapse is reversed3D. A thermonuclear (thermonuclear:adj.高热原子核反应的) shock wave runs through the now expanding stellar envelope, fusinglighter elements into heavier ones and producing a brilliant3A visual outburst that can be asintense as the light of 10 billion suns. The shell of matter thrown off by theexplosion plows through the surrounding gas, producing an expanding bubble ofhot gas, with gas temperatures in the millions of degrees. Thisgas will emit most of its energy at X-ray wavelengths3C
, so it is not surprising that X-rayobservatories have provided some of the most useful insights into the nature ofthe supernova phenomenon. More than twenty supernova remnants have now beendetected in X-ray studies.Recent discoveriesof meteorites with anomalous concentrations ofcertain isotopes indicate that a supernova might have precipitated the birth ofour solar system more than four and a half billion years ago. Although thecloud that collapsed to form the Sun and the planets was composed primarily ofhydrogen and helium, it also contained carbon, nitrogen, and oxygen, elementsessential for life as we know it. Elements heavier than helium are manufactureddeep in the interior of stars and would, for the mostpart (for the most part: adv.在极大程度上), remainthere if it were not for the cataclysmic supernova explosions that blow giantstars apart. Additionally, supernovas produce clouds of high-energy particlescalled cosmic rays (cosmic rays: n. 宇宙线，宇宙射线). These high-energyparticles continually bombard the Earth and are responsible for many of thegenetic mutations that are the driving force of the evolution of species.
3. Accordingto the passage all of the following are true of supernovas EXCEPT that they
(A) areextremely bright
(B) are anexplosion of some sort
(C) emit largequantities of X-rays
(D) result inthe destruction of a neutron star（E）
(E) are causedby the collisionof large galaxies这个根据文章信息就能得出 supernova不是由星系间的碰撞引起的，或者可以采用排除法，无法定位collision

8. Accordingto the passage a neutron star is
(A) a gaseouscloud containing heavy elements
(B) an intermediate stage between an ordinary star and asupernova
没有办法很精确定位是根据文章内容得来的，两个段落讲了a star→a neutron star→supernova这么一个过程
(C) the residuethat is left by a supernova
(D) the core ofan ordinary star that houses the thermonuclear reactions（B）

(E) one ofbillions of meteors that are scattered across the galaxy by a supernova

哈哈你是让斑竹来看啊哈哈
我正好做到这篇就帮你答一下。O(∩_∩)O~

gracezz · 发表于 2010-4-30 20:54:23

谢谢楼上MM~~你做得真细致~~我看明白啦～～～：）

大全补充22篇第四篇-大全67

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